The Department of Foreign Affairs says it has been trying to get access to an Australian man detained in Eritrea since December.

Adrian Troy was working for Protection Vessels International (PVI), a security company working in waters where piracy is rife.

The reason for his detention remains unclear and Eritrean authorities have so far failed to respond to Australia's requests for consular access.

Mr Troy, reportedly a dual national with British and Australian passports, has worked for Arrow Pearls in Broome for 15 years.

Company spokesman Steve Arrow says Mr Troy took a boat to Thailand, where he is normally based, for a refit.

When the job took longer than anticipated he took a fill-in position as a contractor with PVI, a company providing security services to the shipping industry in various troubled waters around the world.

Mr Arrow says it is believed the security company has employed a lawyer.

"I can't say that Adrian's specifically got a lawyer, but I believe the company who has engaged him do have a lawyer acting for them in Eritrea," he said.

"That's what I've been told. It's been over two months now and we've got no contact from Adrian in that time.

"Both the British foreign office and, as far as I can tell, the Australians at this point in time have been unable to speak directly with him and give us an independent third party view as to whether he's safe and healthy."

The last time Mr Arrow had any contact with Mr Troy was when he sent a text on December 12 asking about the cricket.

A planned meeting in Thailand three days later never eventuated and Mr Arrow says it appears diplomatic efforts from both the UK and Australia have been foiled by the Eritrean navy.

"Simply the Eritreans, it would seem, led by their navy, simply won't allow diplomatic people to travel to where the vessel and the crew are being held and therein lies the problem," Mr Arrow said.

He says Mr Troy's family members are concerned.

"It's just been very, very difficult, primarily because we just can't get any information whatsoever. There's absolutely nothing from any source that can give us any satisfaction that he's OK," Mr Arrow said.

An Australian consular official has been sent to Eritrea, but British authorities have been taking the lead on the case.

In London, the minister for Africa has twice summoned the Eritrean ambassador to reiterate requests for access.